Biomedical subjects

H Zwick

Publications and source records attributed to H Zwick.

At least 37 records · Page 2Linked to original sources

PubMed1993

Bronchoalveolar lavage in rheumatoid arthritis.

Bronchoalveolar lavage (BAL) was performed on 70 RA patients, 28 without extra-articular manifestations, nine with pulmonary involvement, 13 with sicca-syndrome, 20 with other extra-articular manifestations such as renal involvement, cutaneous vasculitis and rheumatoid nodules. Fifteen patients without rheumatic or pulmonary disease served as the control group. Compared with the control group RA patients showed a statistically significant increase of lymphocytes, especially of activated (DR+)T(CD3+)-helper (CD4+) cells, resulting in a significantly diminished percentage of alveolar macrophages, B(CD21+)-lymphocytes, T-suppressor (CD8+) cells and an increased CD4/CD8 ratio. This cell distribution pattern was more pronounced in RA patients with lung involvement with significant differences to the other RA patients with regard to lymphocytes, DR positive cells and CD4 positive/DR positive cells. It is concluded that these results indicate an altered balance of immunocompetent cells not only in the joints but also in the lung. The changes are more distinct if local manifestations can be diagnosed clinically.

Aged↗

PubMed1993

The effect of opioids on inspiratory muscle fatigue during inspiratory resistive loading.

The effect of opioids on inspiratory muscle function under high mechanical load is still unknown. Even less clear is the extent to which opioids influence the shift of the electromyographic power spectrum of the inspiratory muscles to lower frequencies during ventilatory stress. We studied seven healthy subjects breathing against high inspiratory threshold loads until exhaustion while keeping the minute ventilation constantly high. We compared runs with and without administration of 0.2 mg kg-1 of morphine sulphate intramuscularly; two subjects were given 30 mg morphine sulphate so that we could study the effect of higher opioid concentration. The endurance time (Tlim), the diaphragmatic electromyogram (EMG), the transdiaphragmatic pressures (Pdi) and the ventilatory effort sensation were analysed. Morphine did not have any effect on Tlim or on the effort sensation elicited by the inspiratory resistance in both concentrations. Analysing the spectral shifts of the diaphragmatic EMG, we did not find any significant difference in the decrease of the centroid frequency between drug and control runs. Furthermore, the activation pattern of the diaphragm and the intercostal muscles, evaluated from the percentage contribution of oesophageal and gastric pressures on the transdiaphragmatic pressure swings, did not change following the administration of morphine. Our study shows that morphine does not change the function of the inspiratory muscles during high-resistive breathing. Morphine does not affect the electromyographic power spectrum of the diaphragm during those resistive breathing runs, either. This points out that during stressful ventilatory situations, the shift of the electromyographic power spectrum is attributed to a peripheral (muscular) event consequent to muscle fatigue and not to the elaboration of endogenous opioids.

Adult↗

PubMed1993

Model for investigating snorers with suspected sleep apnoea.

BACKGROUND: Overnight polysomnography is expensive and time consuming. An approach based on a logistic regression model and overnight pulse oximetry has been developed to determine which of the snorers referred to our sleep laboratory need polysomnography. METHODS: The variables entered in the regression model were derived from questionnaires completed by 95 habitual snorers and 89 patients with obstructive sleep apnoea. The resulting regression equation included weight, height, sex, witnessed episodes of apnoea, and reports of falling asleep when reading. This prediction equation was applied to a sample of 116 consecutive patients referred for investigation of heavy snoring. Pulse oximetry data on the 116 test subjects were obtained during polysomnography and analysed separately. Pulse oximetry was judged to indicate obstructive sleep apnoea when it showed cyclic oscillations of oxyhaemoglobin saturation or heart rate, or both, for more than 30 minutes during the study night. RESULTS: A cut off probability of 0.31 gave the prediction model a sensitivity of 94% to predict an apnoea-hypopnoea index above 10, with a specificity of 45%. When this cutoff point was used to predict an apnoea-hypopnoea index of over 20 sensitivity was 95% and specificity 41%. Combined with oximetry our regression model had a sensitivity of 100% for predicting an apnoea-hypopnoea index of more than 10. On the other hand, all patients with negative results from oximetry and a probability value below 0.31 had an apnoea-hypopnoea index lower than 10 according to polysomnography. CONCLUSIONS: It is concluded that snorers with negative results from oximetry classified as not having obstructive sleep apnoea according to this model do not need polysomnography.

Adult↗

PubMed1993

Nasal CPAP and weight loss in hypertensive patients with obstructive sleep apnoea.

BACKGROUND: The high prevalence of obstructive sleep apnoea (OSA) in patients with systemic hypertension and of hypertension in patients with OSA suggests a causal link between the two disorders. This study was carried out to determine whether nasal continuous positive airway pressure (CPAP) and weight loss affect daytime hypertension in OSA. METHODS: Sixty hypertensive patients with OSA took part in the study; 33 accepted nasal CPAP and used their machine for 5.7 (0.2) hours per night, and the remaining 27 patients refused nasal CPAP and upper airway surgery so the only therapeutic intervention was a recommendation of weight loss. A significant change in hypertension during follow up was defined as either a change in mean blood pressure of at least 10 mm Hg (or more than 8%) without a change in drug treatment, or a reduction in drug dosage with mean blood pressure within these limits. Weight loss was defined as a body mass index of at least 5% below the baseline value. RESULTS: After 512 (41) days, hypertension had become less severe in seven of 12 patients (58%) treated with weight loss only, in eight of 28 patients (29%) with nasal CPAP only, in two of five patients with nasal CPAP and weight loss, and in one of 15 patients without nasal CPAP or weight loss. Multivariate analysis of variance with the outcome of hypertension at follow up as the dependent variable revealed that only the percentage change in body mass index significantly contributed to the course of hypertension. CONCLUSION: The course of hypertension in OSA is more closely linked to weight loss than to elimination of sleep apnoea by nasal CPAP.

Body Mass Index↗

PubMed1993

Endogenous opioid system during inspiratory loading in patients with type I diabetes.

To investigate the activity of the endogenous opioid system in patients with insulin-dependent diabetes mellitus during ventilatory stress situations, we measured plasma beta-endorphin levels in six male and five female diabetic patients breathing against fatiguing inspiratory resistive loads. The patients had to generate with each inspiration an esophageal pressure (Pes) 80% of maximum until they were exhausted and could no longer develop target Pes. The loaded breathing run was repeated three times with a 1-min interval between each run. Duty cycle, tidal volume, and breathing frequency were constant in all tasks. For each run plasma beta-endorphin levels were measured, inspiratory effort sensation assessed using a modified Borg scale, and inspiratory muscle endurance evaluated by the length of time the task could be maintained (Tlim). A group of 11 sex-, age-, height-, and weight-matched healthy individuals served as control subjects. Tlim was significantly lower in the diabetic patients. Evaluating respiratory effort during the three test runs in control subjects at a time corresponding to the break point of loaded breathing in patients showed significantly lower Borg ratings in the control group than in the patient group. Baseline plasma beta-endorphin was significantly lower in the diabetic patients (10.6 +/- 2.1 versus 27.0 +/- 4.2 pg/ml, p < 0.01). Additionally, whereas resistive loaded breathing caused a further increase in plasma beta-endorphin concentration in the control group (p < 0.005), absolutely no increase was found in the diabetic patients. We conclude that the endogenous opioid system in insulin-dependent diabetic patients does not respond to stress caused by breathing against fatiguing inspiratory resistive loads.

Adult↗

PubMed1993

Self-reported vs measured compliance with nasal CPAP for obstructive sleep apnea.

To estimate reliability of self-reported compliance with nasal continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea (OSA), we studied 63 OSA patients aged 53.7 +/- 1.2 years (mean +/- SEM) with an apnea hypopnea index (AHI) of 50.8 +/- 2.9 and lowest sleep SaO2 of 65.6 +/- 2.3 percent receiving nasal CPAP for 539 +/- 44 days. During a follow-up polysomnography (PSG) on the pressure prescribed for home therapy (10.3 +/- 0.3 cm H2O), the hours of operation shown on the built-in time counter of the patients' devices were read to determine objective compliance by dividing the run time by the days since initiation of therapy. This parameter was compared with subjective compliance reported in a self-administered questionnaire. Mean measured use time was 4.9 +/- 0.3 h per night, whereas reported daily use time calculated from reported nights a week and hours a night was 6.1 +/- 0.3 h per night. As predominantly patients with poor compliance misestimated daily use time, we conclude that self-reports are unable to distinguish between compliant and noncompliant patients.

Female↗

PubMed1993

No effect of naloxone on ventilatory response to progressive hypercapnia in IDDM patients.

The ventilatory response to hyperoxic progressive hypercapnia was examined by comparing 3 test groups: 7 diabetic patients with AN, 8 diabetic patients without AN, and 8 normal control subjects. In each group, a significant linear correlation was found between PaCO2 and VE. The slopes of the regression curves relating PaCO2 to VE were significantly steeper in the healthy control subjects and diabetic patients without AN than in those with AN (P < 0.01). We conclude that the ventilatory response to progressive hypercapnia is reduced in diabetic patients with AN. By analyzing the power spectrum and the amplitude behavior of the diaphragmatic EMG (calculated from the fc and RMS, respectively), we could exclude a disturbance of neural descending pathways and respiratory muscle dysfunction as possible causal mechanisms for the impaired ventilatory response to increasing CO2. By using lung function analysis, causal factors such as alterations in respiratory system mechanics also could be excluded. As diabetes is known to affect the endogenous opioid system, which, in turn, affects the ventilatory response to CO2, naloxone, as a specific opioid antagonist, was administered in all 3 test groups. Naloxone produced a significant increase of ventilatory response to hypercapnia in the healthy control subjects (P < 0.01), but produced no effect in either of the diabetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Comparison of the properties and concentrations of the isoforms of retinol-binding protein in animals and human beings.

We used size-exclusion high-performance liquid chromatography (HPLC) to investigate the properties of the 2 isoforms of Vitamin A-containing (holo) retinol-binding protein (RBP) in animals: the form that is bound to transthyretin (holo-TTR-RBP), and the form that does not bind to TTR (holo-free RBP). We also used radial immunodiffusion to measure immunologically active RBP (apo + holo RBP). We compared the isoforms of RBP in animals with those of human beings to determine which animal is the best model of human RBP. Size-exclusion HPLC detected holo-free and holo-TTR-RBP in every animal species studied. Apparent concentration of holo-TTR-RBP varied among species: that of rabbits and dogs >> that of apes, sheep, goats, monkeys, rhinoceroses, felids, rats, human beings, and deer > that of pigs, zebra, and bison > that of penguins. Dogs have unusual RBP chromatograms; they have high concentration of RBP, but also appear to transport much of their vitamin A on protein other than RBP. Human RBP antibody preparations could detect apo + holo RBP immunologic activity only in apes, monkeys, and felids. Apes and monkeys appeared to have complete cross-reactivity to human RBP antibodies. Felids may have substantial, but partial, cross-reactivity. Apes and monkeys appear to be the most relevant animal models for study of human RBP transport. However, there is a need for less-expensive models. Further research is needed, but in the interim, rats or sheep may be satisfactory for some purposes.

Animals↗

PubMed1993

Inspiratory muscle performance relative to the anaerobic threshold in patients with COPD.

Rehabilitation programmes in chronic obstructive pulmonary disease (COPD) require exercise training above the anaerobic threshold. However, not all COPD patients develop metabolic acidosis during exercise. The hypothesis of this study was that non-exercise variables, characterizing the mechanical load on the inspiratory muscles during breathing at rest, can be used to reliably predict which patients with COPD are not able to develop metabolic acidosis during exercise. Thirty participants with COPD performed a symptom-limited cycle ergometer test. The oesophageal pressure/time index (PTIoes: the product of pressure magnitude and duration), the mean rate of pressure development during inspiration (Poes/TI), and the mean airway resistance (Raw)/maximal oesophageal pressure (Poesmax) ratio served as indices for the mechanical load on the inspiratory muscles. The oxygen uptake (VO2) at which plasma standard bicarbonate was seen to decrease from its baseline value was taken as the anaerboic threshold (AT). Mean Raw was significantly higher in those patients in whom the AT could not be detected. No other lung function parameters measured at rest allowed the accurate selection of those patients who did or did not develop exercise metabolic acidosis. On the other hand, Raw/Poesmax, PTIoes and Poes/TI were significantly different in the two patient groups. Additionally, whereas in the patient group with identifiable AT exercise hyperpnoea produced a non-linear increase of Poes/TI with respect to PTIoes above the AT, in the patient group without identifiable AT there was a linear relationship between Poes/TI and PTIoes throughout exercise. We conclude that the determination of inspiratory muscle load indices at rest may be useful in pulmonary rehabilitation programmes, for identifying those patients with COPD who do not develop exercise induced metabolic acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobic Threshold↗

PubMed1993

Inspiratory muscle performance relative to the ventilatory threshold in healthy subjects.

Inspiratory muscle performance, ventilation, and gas exchange were studied during exercise in healthy subjects to look for typical changes of pattern of contraction at the ventilatory threshold (VT). The steepening of the slope of carbon dioxide output (VCO2) vs oxygen uptake (VO2) at the VT was accompanied by a nonlinear increase of the mean rate of esophageal pressure development (Pes/TI) vs the esophageal pressure time index (PTIes) reflecting both the relative force (Pbreath/Pesmax) and duration (TI/TTOT) required for inspiration. The esophageal pressure time integral within one breath (Pbreath.dTI) was one of the best single predictors of the ventilatory equivalent for oxygen (VE/VO2) at the VT. Moreover, we presented inspiratory muscle load indices as a mirror image of breathing pattern, with the obvious advantage that the ventilation component can be compared with better established methods of presenting ventilatory output. Inspiratory muscle performance during exercise should link the increased metabolic rate to ventilatory output. We conclude that 1) there exists an inspiratory muscle threshold that is well correlated to commonly used gas exchange thresholds, and 2) the efficiency of ventilation and gas exchange during exercise could be linked to pressure and timing of inspiratory muscle contraction.

Adolescent↗

PubMed1993

[Allergic rhinitis, respiratory obstruction and bronchial asthma in the Vienna population].

In the present study the incidence of bronchial asthma, airway complaints, and allergic rhinitis was investigated in a randomized population section including 3000 male and female inhabitants of Vienna (sex ratio 1:1), aged 20-44. Data on complaints in the respiratory tract were obtained from a total of 71% of the study population. Our results suggest that 14.7% of the entire population was suffering from allergic rhinitis (16.4% male versus 13.0% female; p < 0.05). Airway complaints such as wheezing, whistling, and feeling of tightness in the chest, awakening because of shortness of breath or cough were frequently reported, with no major differences between male and female subjects. The overall percentage of study subjects stating that they had suffered from airway complaints in the year before, i.e., the percentage of those giving affirmative answers to one of the questions, was 29%. Bronchial asthma was calculated to be present in 5.1% of the entire population (5.9 male versus 4.4 female). Attacks of asthma were reported by only 2.2% of the subjects, which gives an indication of the discrepancy between identified and unidentified bronchial asthma. Allergic rhinitis is correlated to, and constitutes a risk factor for the occurrence of complaints in the respiratory tract; public health policy should therefore be aimed at the prevention or early treatment of allergic rhinitis, and at reducing the proportion of cases suffering from unidentified bronchial asthma.

Adult↗

PubMed1992

How much brushing is enough for the diagnosis of lung tumors?

BACKGROUND: Bronchoscopic investigations of lung tumors require high diagnostic accuracy. Sometimes the combination of brush biopsy with cytologic and histologic examination of forceps-obtained biopsy specimens fails to diagnose tumors. Techniques with a minimum risk and low cost when repeated several times could increase the efficiency of tumor diagnosis and help to avoid rebronchoscopy. METHODS: Repeated brush biopsies were done during one bronchoscopic examination in 270 patients with pulmonary neoplasias using a flexible fiberoptic bronchoscope guided by radiographic video fluoroscopy. The results of up to five brush biopsies were compared for their diagnostic sensitivity. RESULTS: Singly, 68-77% of the specimens showed malignant findings. With repeated brushing, the sensitivity of the diagnostic accuracy increased to 89.6%. In the periphery of the bronchial tree, the sensitivity of brush biopsy was slightly lower in bronchoscopically invisible tumors. In 222 of 242 (91.7%) patients with positive results of brush biopsy, there was agreement in the final typing of tumor morphology. CONCLUSION: For routine bronchoscopy, repeated brush biopsy should be done to obtain the highest diagnostic yield.

Adenocarcinoma↗

PubMed1992

Effect of posture on inspiratory muscle electromyogram response to hypercapnia.

The aim of our study was to examine the effect of posture on inspiratory muscle activity response to hypercapnia. Recent research has revealed that in normal subjects the activation of the rib cage muscles and of the diaphragm is actually greater in the upright than in the supine position during resting tidal breathing. In this study we examined whether the upright position necessarily entails a greater activation of the inspiratory muscles also under conditions of ventilatory stress. For this purpose we compared the responses to CO2-rebreathing in the supine and sitting positions in five volunteers, by simultaneously recording the electromyogram of the diaphragm (EMGdi) and the intercostal muscles (EMGint). The electromyogram was recorded by means of surface electrodes to measure the EMG amplitude. While the slopes of ventilatory (VE) response to increasing arterial CO2 tension (PaCO2) were similar in the two positions, both the EMGdi-VE and EMGint-VE relationship showed steeper slopes in the supine than in the sitting position. In each CO2 run the increases in EMGdi were linearly related to those in EMGint. This relationship was not affected by the body position. These results suggested that, in spite of similar ventilatory responses to CO2-rebreathing in the lying and sitting positions, the supine position, in humans, required a higher activation of the inspiratory muscles.

Adult↗

PubMed1992

Mechanical load on the inspiratory muscles during exercise hyperpnea in patients with type 1 (insulin-dependent) diabetes mellitus.

The aim of this study was to evaluate the difference between Type 1 (insulin-dependent) diabetic patients and healthy control subjects regarding inspiratory muscle load during exercise hypernea. For this purpose an incremental progressive exercise test on a cycle ergometer was performed by 36 Type 1 diabetic patients and 40 healthy subjects. In order to determine the mechanical load on the inspiratory muscles breath by breath, we selected the following two parameters, which represent the pressure generated by the inspiratory muscles as well as the duration and velocity of their contraction: (1) the oesophageal tension time index, which is the product of the duty cycle (ratio of inspiratory time to total breath cycle duration) and the mean oesophageal pressure expressed as a percentage of the maximal oesophageal pressure and (2) the mean oesophageal pressure change per time unit during the inspiratory phase of each breathing manoeuver, which is expressed as a fraction of the subject's maximal oesophageal pressure. Comparison of the two groups revealed that at similar levels of ventilation the mechanical load on the inspiratory muscles was significantly higher in the Type 1 diabetic patients than in the control subjects. When the loading was stopped the maximal ventilation was lower in the patients. Nevertheless, they reported a degree of respiratory effort sensation comparable to the control group, which seems to have been caused by an increase of the mechanical load on the ventilatory muscles.

Adult↗

PubMed1992

Nucleolar silver staining patterns of lymphocytes in sarcoidosis.

Bronchoalveolar lavage lymphocytes from 15 patients with pulmonary sarcoidosis and 8 healthy controls were investigated for nucleolar silver staining patterns and lymphocyte subpopulations. Patients with sarcoidosis had increased numbers of silver stained dots versus controls (2.20 +/- 0.24 versus 1.78 +/- 0.07; p less than 0.001). The number of silver stained dots showed the strongest positive correlation to helper cells (OKT 4+) (r = 0.781; p less than 0.0001). These results may be interpreted as further evidence of lymphocytic activation, especially of helper cells (OKT 4+) in pulmonary sarcoidosis.

Adult↗

PubMed1992

Horse chestnut (Aesculus hippocastanum) pollen: a frequent cause of allergic sensitization in urban children.

We investigated the incidence of allergic sensitization and the risk factors underlying sensitization in 214 urban children exposed to horse chestnut pollen. By means of the Phadezym RAST, we found IgE specific to horse chestnut pollen in 12.6% of the urban children, whereas it occurred in only 1.9% of control subjects recruited from a rural area. Reports of allergic symptoms in spring during the horse chestnut pollen load coincided with the presence of specific IgE in 5.1% of the urban group as against 1.4% of the recruited from the rural area. Environmental factors other than those related to urban living and higher horse chestnut pollen counts had no significant impact on allergic sensitization. Increased total IgE levels (greater than 100 kU/l), however, and the sensitization to pollen of other species significantly raised the odds for sensitization to chestnut pollen. They were highest in highly atopic children with sensitization to pollen, especially to that of plane trees (OR = 73.9). These results suggest the relevance of horse chestnut pollen because of the high allergic sensitization rate among urban children, and they should also be borne in mind when it comes to the planting of trees in urban areas.

Allergens↗

PubMed1992

Pulmonary gas exchange and oxygen uptake during exercise in patients with type 1 diabetes mellitus.

In order to investigate pulmonary gas exchange and cardiopulmonary performance in Type 1 diabetes, 36 patients underwent a progressive incremental exercise test on a cycle ergometer. Cardiopulmonary variables were measured, and arterial blood gases determined on samples obtained from an indwelling catheter in the radial artery. The results were compared with those from 40 control subjects. In the patients, the maximum power (Wmax) and maximum oxygen uptake (VO2max) were lower than in the control subjects (Wmax 186 +/- 52 (+/- SD) vs 233 +/- 48 W, p less than 0.05; VO2max 2.56 +/- 0.71 vs 3.17 + 0.77 l min-1, p less than 0.05). At comparable levels of power output, however, no significant abnormality was observed in the difference between alveolar and arterial oxygen pressure (P(A-a)O2), and the ratio of physiological dead space to tidal volume (VD/VT ratio). These data indicate that in Type 1 diabetic patients, despite their reduced maximum oxygen uptake, gas transfer during exercise is not limited and thus does not contribute to the impairment of exercise capacity.

Adult↗

PubMed1992

Influences of the cellular and humoral immune system in bronchoalveolar lavage on lung function in pulmonary sarcoidosis.

We investigated the changes in the cellular and humoral immune system in bronchoalveolar lavage (BAL) performed in 22 patients with pulmonary sarcoidosis and in 14 normal control subjects and their interactions with lung function parameters. Lymphocytosis, the increase in OKT4+ lymphocytes and OKT4+OKDR+ lymphocytes correlated with the increase in immunoglobulins, especially IgG, IgA and kappa chain assembled immunoglobulins. The transferrin levels obtained in BAL were found to be higher in patients with sarcoidosis, and they correlated with the cellular and, more closely, with other humoral findings. A negative correlation existed between the ventilatory parameters and the cell count and humoral findings. In addition, we found a negative correlation between the diffusing capacity for carbon monoxide and other cellular findings, which was most pronounced with reference to lymphocytes, OKT4+ lymphocytes and the OKT4+/OKT8+ ratio. These results underscore the role of OKT4+ lymphocytes, activated OKT4+OKDR+ lymphocytes and transferrin in the increase in immunoglobulins, mainly kappa chain isotypes. Because of the relationship between these changes and ventilatory parameters, and the diffusing capacity, the above results also reveal the clinical relevance of our findings.

Adult↗